Abstract: The invention relates to a method for producing noble metal nets on flatbed knitting machines, the steps involving—providing noble metal wire comprising platinum—providing yarn that is combustible or soluble in solvent—knitting two-bed items by simultaneous knitting on the front and rear needle beds and joining the two knitted fabrics by means of connecting pile threads, wherein, on the front or on the rear needle bed, a combustible or soluble yarn is used which is burnt off or dissolved after the knitting process, and a noble metal wire is used on the other needle bed and for the pile threads such that, after the combustible or soluble yarn has been burnt off or dissolved, there remain only the pile threads and the knitted fabric made of noble metal wire and produced on the rear or front needle bed.

Abstract: Wire for weaving or knitting a catalyst gauze, said wire being characterized in that it is a stranded wire comprising an assembly of n intertwined filaments, n being an integer with 2?n?8, wherein each of said filaments comprises Pt or a Pt alloy constituted of at least 50% by 5 weight of Pt, said filaments being twisted together over their length so that each of the filaments is wound to at least one other filament.

Abstract: The invention is directed to a method for determining the state of aging of a catalytic converter (2). The disclosed method functions in a non-contacting manner as resonances formed when the catalytic converter (2) located in a housing is excited with high-frequency electromagnetic waves are analyzed.

Abstract: The invention is directed to a method for determining the state of aging of a catalytic converter (2). The disclosed method functions in a non-contacting manner as resonances formed when the catalytic converter (2) located in a housing is excited with high-frequency electromagnetic waves are analyzed.

Abstract: The present invention relates to a process for determining the state of an exhaust-gas purification device. The exhaust-gas purification device is one which can store gas and/or particles. By means of the proposed process, it is for example possible for the loading state of the exhaust-gas aftertreatment system, for example the oxygen storage state of a catalytic converter which is provided with an oxygen-storing material, such as for example a three-way catalytic converter, to be analyzed. The present process operates contactlessly through the analysis of resonances which arise upon the excitation of the catalytic converter using the purification device as microwave cavity resonator.

Abstract: The present invention relates to a process for determining the state of an exhaust-gas purification device. The exhaust-gas purification device is one which can store gas and/or particles. By means of the proposed process, it is for example possible for the loading state of the exhaust-gas aftertreatment system, for example the oxygen storage state of a catalytic converter which is provided with an oxygen-storing material, such as for example a three-way catalytic converter, to be analysed.

Abstract: The present invention relates to an exhaust-gas aftertreatment system which comprises a preferably catalytically active particle filter (wall-flow filter) which is followed in turn by a throughflow monolith (flow-through monolith) which is preferably provided with a catalytically active function. Both components have the same storage functions for gaseous substances present in the exhaust gas of internal combustion engines. The system is suitable in particular for the simultaneous removal of particles and pollutants from the exhaust gas of both predominantly lean-operated internal combustion engines and also of internal combustion engines operated predominantly with a stoichiometric air/fuel mixture. Likewise described is a process for the production and the use of such a system for exhaust-gas aftertreatment.

Abstract: Described is a method for cleaning the exhaust gases of internal combustion engines, which method is suitable for reducing harmful gases and particle emissions. Here, the exhaust gas to be cleaned is conducted, under operating conditions, with a discontinuous profile of the air ratio ? across a wall-flow filter substrate which comprises a catalytically active coating containing one storage material. The storage material is suitable for temporarily storing one or more exhaust-gas components under certain operating conditions and releasing said exhaust-gas components again in a targeted fashion in the event of a suitable change in the operating conditions. The coating is configured such that the component has a gradient of the storage material concentration and/or of the total coating amount, with the highest concentration of the storage material in the longitudinal direction of the component being present on the inflow side.

Abstract: When a nitrogen oxide storage catalyst is being regenerated, the regeneration may be terminated for example as a result of a premature load change in the engine, which can lead to incomplete emptying of the storage catalyst. The residual filling level which remains in the catalyst following an incomplete regeneration of this nature is used as the starting value for calculation of the filling level during the next storage phase. After incomplete regeneration, the nitrogen oxide conversion rate is initially greater than would be expected, on account of the residual filling level. By taking this increased conversion rate into account when calculating the filling level during the storage phase, it is possible to further improve the accuracy of the calculation.

Abstract: The invention describes a method for determining the light-off temperature of a catalytic converter on board a vehicle. The aging condition of the catalytic converter is determined by means of the method. To test the catalytic converter, the latter is loaded for example with a CO/HC test pulse. During the combustion of the additional CO and HC on the catalytic converter, an axial temperature profile is generated. The position of the maximum of said temperature profile along the catalytic converter is dependent on the current light-off temperature. The temperature profile travels through the catalytic converter and can be measured at the outlet of the catalytic converter as a time-dependent profile. The original axial temperature profile can be inferred from the time-dependent profile. Using a calculation program, the current light-off temperature of the catalytic converter on the vehicle can be determined.

Abstract: The present invention relates to an exhaust-gas aftertreatment system which comprises a preferably catalytically active particle filter (wall-flow filter) which is followed in turn by a throughflow monolith (flow-through monolith) which is preferably provided with a catalytically active function. Both components have the same storage functions for gaseous substances present in the exhaust gas of internal combustion engines. The system is suitable in particular for the simultaneous removal of particles and pollutants from the exhaust gas of both predominantly lean-operated internal combustion engines and also of internal combustion engines operated predominantly with a stoichiometric air/fuel mixture. Likewise described is a process for the production and the use of such a system for exhaust-gas aftertreatment.

Abstract: The present invention relates to a method for purifying the exhaust gases of an internal combustion engine having a catalytic converter which comprises oxygen storage components. The invention is concerned particularly with the restoration of the optimum filling degree of the oxygen storage components for regulated stoichiometric operation after the engine has been operated under lean conditions for a relatively short or relatively long period of time.

Abstract: The present invention describes an exhaust-gas purification system for an internal combustion engine made of an oxidation catalyst arranged close to the engine, a subsequent hydrocarbon adsorber and a particulate filter arranged downstream thereof and provided with another oxidation catalyst. The oxidation catalyst ensures that emission limits with respect to carbon monoxide and hydrocarbons are satisfied in normal driving mode. During operating states with exhaust-gas temperatures below about 200° C., the oxidation catalyst can no longer oxidize carbon monoxide and hydrocarbons. Instead, the hydrocarbons are adsorbed by the hydrocarbon adsorber during these operating phases. In order to initiate the periodical regeneration of the particulate filter, the exhaustgas temperature of the internal combustion engine is raised by engine modifications.

Abstract: A cost effective process is presented for carrying out catalytic, in particular also exothermic, endothermic or autothermal reactions with optimum yield and selectivity. The system used is a wall-flow monolith which forces a flow from the inlet channel through the porous wall into the outlet channel by reciprocal closure of the gas channels. This is operated such that mass transfer and heat transport are determined virtually exclusively by convection, and diffusion-related thermal conduction phenomena can be neglected.

Abstract: Described is a method for cleaning the exhaust gases of internal combustion engines, which method is suitable for reducing harmful gases and particle emissions. Here, the exhaust gas to be cleaned is conducted, under operating conditions, with a discontinuous profile of the air ratio ? across a wall-flow filter substrate which comprises a catalytically active coating containing one storage material. The storage material is suitable for temporarily storing one or more exhaust-gas components under certain operating conditions and releasing said exhaust-gas components again in a targeted fashion in the event of a suitable change in the operating conditions. The coating is configured such that the component has a gradient of the storage material concentration and/or of the total coating amount, with the highest concentration of the storage material in the longitudinal direction of the component being present on the inflow side.

Abstract: The invention describes a method for determining the light-off temperature of a catalytic converter on board a vehicle. The aging condition of the catalytic converter is determined by means of the method. To test the catalytic converter, the latter is loaded for example with a CO/HC test pulse. During the combustion of the additional CO and HC on the catalytic converter, an axial temperature profile is generated. The position of the maximum of said temperature profile along the catalytic converter is dependent on the current light-off temperature. The temperature profile travels through the catalytic converter and can be measured at the outlet of the catalytic converter as a time-dependent profile. The original axial temperature profile can be inferred from the time-dependent profile. Using a calculation program, the current light-off temperature of the catalytic converter on the vehicle can be determined.

Abstract: When a nitrogen oxide storage catalyst is being regenerated, the regeneration may be terminated for example as a result of a premature load change in the engine, which can lead to incomplete emptying of the storage catalyst. The residual filling level which remains in the catalyst following an incomplete regeneration of this nature is used as the starting value for calculation of the filling level during the next storage phase. After incomplete regeneration, the nitrogen oxide conversion rate is initially greater than would be expected, on account of the residual filling level. By taking this increased conversion rate into account when calculating the filling level during the storage phase, it is possible to further improve the accuracy of the calculation.

Abstract: This invention relates to a method of operating a catalyst for treating the exhaust gas of an internal combustion engine, the catalyst comprising, in addition to catalytically active noble metals, also storage components for storing hydrocarbons. During engine operating phases at low exhaust-gas temperatures, such a catalyst stores the hydrocarbons contained in the exhaust gas without burning them. When the exhaust-gas temperature rises, these hydrocarbons are desorbed again and then oxidized at the catalytically active noble metals. This process can lead to uncontrolled, vigorous combustion of the hydrocarbons stored on the catalyst and, therefore, damage to the catalyst. According to the invention, this damage is avoided by continuously calculating the respective loading of the storage components with hydrocarbons and repeatedly regenerating the storage components depending on the loading by temporarily raising the exhaust-gas temperature before damage to the catalyst can occur.

Abstract: When a nitrogen oxide storage catalyst is being regenerated, the regeneration may be terminated for example as a result of a premature load change in the engine, which can lead to incomplete emptying of the storage catalyst. The residual filling level which remains in the catalyst following an incomplete regeneration of this nature is used as the starting value for calculation of the filling level during the next storage phase. After incomplete regeneration, the nitrogen oxide conversion rate is initially greater than would be expected, on account of the residual filling level. By taking this increased conversion rate into account when calculating the filling level during the storage phase, it is possible to further improve the accuracy of the calculation.

Abstract: An oxygen storage material comprising cerium oxide and at least one second oxide of a metal M1 is disclosed as well as a process for manufacturing the material and the use of this material in an exhaust gas cleaning catalyst. In a preferred embodiment the oxygen storage material comprises particles from a Ce/M1 mixed oxide solid solution coated with an oxide of another metal M2. Metal M1 e.g. can be calcium or zirconium while metal M2 most preferably is aluminum.